The new atomic age: Building smaller, greener electronics

Published on: 7th Jul 2014

Note -- this news article is more than a year old.

In the drive to get small, Robert Wolkow and his lab at the University of Alberta are taking giant steps forward.

The digital age has resulted in a succession of smaller, cleaner and less
power-hungry technologies since the days the personal computer fit atop a desk,
replacing mainframe models that once filled entire rooms. Desktop PCs have since
given way to smaller and smaller laptops, smartphones and devices that most of
us carry around in our pockets.

But as Wolkow points out, this technological shrinkage can only go so far
when using traditional transistor-based integrated circuits. That's why he and
his research team are aiming to build entirely new technologies at the atomic
scale.

"Our ultimate goal is to make ultra-low-power electronics because that's
what is most demanded by the world right now," said Wolkow, the iCORE Chair
in Nanoscale Information and Communications Technology in the Faculty of
Science. "We are approaching some fundamental limits that will stop the
30-year-long drive to make things faster, cheaper, better and smaller; this will
come to an end soon.

"An entirely new method of computing will be necessary."

Atomic-scale electronics

Wolkow and his team in the U of A's physics department and the National
Institute for Nanotechnology are working to engineer atomically precise
technologies that have practical, real-world applications. His lab already made
its way into the Guinness Book of World Records for inventing the world's
sharpest object-a microscope tip just one atom wide at its end.

They made an earlier breakthrough in 2009 when they created the smallest-ever
quantum dots-a single atom of silicon measuring less than one nanometre
wide-using a technique that will be awarded a U.S. patent later this month.

Quantum dots, Wolkow says, are vessels that confine electrons, much like
pockets on a pool table. The dots can be spaced so that electrons can be in two
pockets at the same time, allowing them to interact and share electrons-a
level of control that makes them ideally suited for computer-like circuitry.

"It could be as important as the transistor," says Wolkow. "It
lays the groundwork for a whole new basis of electronics, and in particular,
ultra-low-power electronics."

New discoveries pave way for superior nanoelectronics

Wolkow and his team have built upon their earlier successes, modifying
scanning tunnelling microscopes with their atom-wide microscope tip, which emits
ions instead of light at superior resolution. Like the needle of a record
player, the microscopes can trace out the topography of silicon atoms, sensing
surface features on the atomic scale.

In a new paper published in Physical Review Letters, post-doctoral
fellow Bruno Martins together with Wolkow and other members of the team,
observed for the first time how an electrical current flows across the skin of a
silicon crystal and also measured electrical resistance as the current moved
over a single atomic step.

Wolkow says silicon crystals are mostly smooth except for these atomic
staircases-slight imperfections with each step being one atom high. Knowing
what causes electrical resistance and being able to record the magnitude of
resistance paves the way to design superior nanoelectronic devices, he says.

In another first, this time led by PhD student Marco Taucer, the research
team observed how single electrons jump in and out of the quantum dots, and
devised a method of monitoring how many electrons fit in the pocket and
measuring the dot's charge. In the past, such observations were impossible
because the very act of trying to measure something so extraordinarily small
changes it, Wolkow says.

"Imagine that if you looked at something with your eyes, the act of
looking at it bent it somehow," he says. "We now can avoid that
perturbation due to looking, and so can access and usefully deploy the dots in
circuitry."

The team's findings, also published in Physical Review Letters, give
scientists the ability to monitor the charge of quantum dots. They've also found
a way to create quantum dots that function at room temperature, meaning costly
cryogenics is not necessary.

"That's exciting because, suddenly, things that were thought of as
exotic, far-off ideas are near. We think we can build them."

Taking the next generation of electronics to the market

Wolkow and his team believe so strongly in the commercial potential of
atomic-scale circuitry, two years ago they launched their own spinoff company,
Quantum Silicon Inc. Over the next five to six years, QSI plans to demonstrate
the potential of these "extremely green" circuits that can make use of
smaller, longer-lasting batteries.

It also moves them from the realm of basic to applied research and real-world
scenarios, Wolkow says.

"We have this nice connection where we have a training ground for
students and highly academic ambitions for progress, but those things quite
naturally and immediately transfer to this practical entity."

Much of their efforts initially will focus on creating hybrid
technologies-adding atom-scale circuitry to conventional electronics such as
GPS devices or satellites, like replacing one link in a chain given the
time-intensiveness of making the new circuits. It could take a decade before
it's possible to mass-produce atom-scale circuitry, but the future potential is
very strong, Wolkow says.

"It has the potential to totally change the world's electronic basis.
It's a trillion-dollar prospect."

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